The present invention relates to an improved spray gun of the syphon cup type, and in particular to such a spray gun having a vented fluid supply container and means connected with the vent for preventing dripping of fluid therefrom upon movement of the gun, and for selectively generating within the container a positive pressure to increase the fluid flow rate from the gun.
In the use of syphon cup type paint spray guns, paint is syphoned through a tube from a supply container into an air stream passing through the gun for discharge in a spray from an orifice in a nozzle of the gun. Since during spraying the volume of paint within the container decreases, the container is vented to atmosphere to prevent a negative pressure from developing therein, with a resultant failure of paint to be syphoned into the gun.
With such spray guns paint within the container may pass through the vent and drip therefrom upon manipulation of the gun. Such dripping is not only undesirable, but is intolerable where it falls upon and mars an otherwise smoothly painted ware. Furthermore, with such guns the paint flow rate or output therefrom is limited by the negative pressure which may be generated within the syphon tube by the stream of air passing over an end of the tube within the gun, and is often less than desired.
Accordingly, an object of the present invention is to provide an improved syphon cup type spray gun assembly which eliminates dripping of fluid from a vented supply container.
Another object of the invention is to provide a syphon cup type spray gun assembly operable to increase the fluid flow rate from the gun per unit of time.